What is the structure of nitrite?

Question

I know that $\ce{NO2}$ has 3 effective pairs, so it is likely to have trigonal planar structure. In trigonal planar structure we usually see three atoms bonded to central atom at 120°. But in $\ce{NO2-}$, I observe that though it has three effective pairs, but still, it is not having the desired structure, with only 2 O atoms bonded to N atom. Can anyone explain the situation?

Answer 1

Nitrogen is actually surrounded by 3 effective pairs. But 2 of them are bonding and the third one is a lone pair. According to VSEPR theory, the structure should be trigonal planar.

• The angle is not exactly $120^\circ$, as the electrostatic repulsion between non-bonding pair and bonding pair is higher than the repulsion between two bonding pair. So, the angle of $\ce{O-N-O}$ is slightly smaller than $120^\circ$.
• The distribution of the three electron effective pairs is trigonal planar. But the molecule structure is bent (like letter V).